Rigid structural supports presently in use such as front end assemblies of automobiles, can include box sections to obtain high strengths. In the metal working industry, these box sections are formed by roll forming sections which are welded into the form of the box sections. Such box sections have been made from composite materials. In the composite industry, flat sections are bonded into open "C" channels to obtain the box sections. Alternatively, such box sections can be made from metal sheets. the sheet molding process, transverse vertical ribs connect the walls of the open "C" sections to give the formed members high strength. In each of the aforementioned processes, a box section is made to provide strength.
It is presently desirable to manufacture modular integrated assemblies wherein a single structural support is used to support the energy absorbing material, as well as other modular units such as the head light assembly. Unlike prior art processes which either utilizes high weight material such as metals or composite processes which require various steps, the present invention provides a method of fabricating a high strength composite material with a minimum amount of steps so as to provide a light weight unitary structural component.
The U.S. Pat. Nos. 2,739,350 to Lampman, issued Mar. 27, 1956 and 4,615,855 to Orlowski et al, issued Oct. 7, 1986 relate to methods and means of forming or molding composite articles. The Lampman patent discloses a method including the steps of applying a thermosetting plastic material to the exterior surface of a preformed interior mold which is preferably made of a material from a thermoplastic group, at a temperature where the thermoplastic interior mold is normally firm. The material covered mold is enclosed inside of a rigid exterior mold. The interior mold is pressurized to maintain the mold in a rigid state. The applied plastic material is cured while the interior mold is pressurized. The pressure from the interior mold is removed when the cure is completed and the exterior mold is removed. The interior mold is removed from the formed part at a temperature where the interior mold is thermoelastic and capable of being deformed for easy removal.
The Orlowski et al patent discloses a process for forming a composite article including the steps of making a plug from a meltable material and covering the plug with a polymerizable material. The covered plug is inserted into a cavity formed in a thermally expansive and heat resistant polymer held within a rigid container. The almost filled container is covered and the container and part are heated to cause curing of the polymerizable covering. The cured assemblies are removed from the thermally expansive and heat resistant polymer and heated to an extent sufficient to melt the core. Thusly, both the Lampman and Orlowski et al patents disclose methods of forming hollow core members.
The U.S. Pat. No. 2,476,993 to Milton, Jr. et al, issued July 24, 1949 discloses a wax core with a metal mold covering formed by spraying on the core. The core is melted to leave a hollow metal mold for gloves.
The U.S. Pat. No. 3,410,942 to Bayer, issued Nov. 12, 1968 discloses a polystyrene pattern covered with a thin layer of polyvinyl. Metal is cast into a mold to vaporize the pattern as the metal molding is formed.
The U.S. Pat. No. 3,518,338 to Tambussi, issued June 30, 1970 discloses a process in which fiberglass is impregnated with resin. A water soluble forming mandrel is removed from the cured part to form a hollow core.
The U.S. Pat. No. 3,758,653 to Patel et al, issued Sept. 11, 1973 discloses a ceramic form process which uses a polystyrene mandrel which is dissolved by gasoline.
The U.S. Pat. Nos. 3,840,626 to Laskawy et al, issued Oct. 8, 1974; 4,040,163 to Tronsberg, issued Aug. 9, 1977; 4,271,116 to Jones, issued June 2, 1981; 4,590,026 to Goto, issued May 20, 1986 disclose other processes in which a mold armature is dissolved to form a hollow part.
The U.S. Pat. Nos. 3,234,309 to Graff, issued Feb. 8, 1966; 4,122,142 to Lawrence et al, issued Oct. 24, 1978; and 4,314,964 to Ferrary, issued Feb. 9, 1982 disclose processes in which a mold armature is inflated to form the part. The armature is deflated and removed after the part is molded.
None of the aforementioned processes relate to reaction injection molding chemistry or tooling or the specific steps disclosed as the present invention or the specific assemblies and parts made therewith.